Security is being stepped up in the northern part of Kosovska Mitrovica, a town about 45 kilometers north of Kosovo's capital, Pristina.
The town is divided between the Serb-dominated north and the ethnic Albanian-dominated south.
Two ethnic Serbs were attacked and wounded in the town on 26 December. A grenade attack in the town on 28 December caused no injuries.
The UN, which has administered the Serbian province since it intervened to end violence in 1999, is currently trying to broker an agreement on the final status of the territory. Ethnic Albanians are seeking independence, while Belgrade insists that Kosovo should remain part of Serbia and Montenegro.